Effect of nano-Al₂O₃on erosion–corrosion behaviour of composite alloying layer under two phase flow conditions

Abstract

The present study was focused on understanding the effect of the added nano-Al 2 O 3 on erosioncorrosion behaviour of composite alloying layer. The nano-Al 2 O 3 reinforced composite alloying layer was prepared by duplex surface treatment, which consisted of Ni/nano-Al 2 O 3 predeposited by brush plating and a subsequent surface alloying with Ni-Cr-Mo-Cu by double glow process on the surface of AISI 316L stainless steel. Current response with applied potential, potentiodynamic polarisation curve, electrochemical impedance spectroscopy and weight loss techniques were applied to evaluate the erosion-corrosion behaviour of composite alloying layer compared with the single alloying layer and 316L stainless steel under hydrodynamic conditions. Results of electrochemical measurements showed that the erosion-corrosion resistance of composite alloying layer was lower than that of single alloying layer when the rotating velocity of tested samples was below 2?51 m s 21 , whereas the erosion-corrosion resistance of composite alloying layer was higher than that of single alloying layer when the rotating velocity of tested samples above 2?51 m s 21 . The weight loss rate studies and surface analysis suggested that the dispersive undissolved nano-Al 2 O 3 particles and c9 prime (Ni 3 Al) phase were helpful to improve the erosion-corrosion resistance of composite alloying layer at high rotational speed, though the c9 prime phase was deleterious to corrosion resistance of composite alloying layer. Xu et al. Effect of nano-Al 2 O 3 on erosion-corrosion behaviour of composite alloying layer Corrosion Engineering, Science and Technology 2011 VOL 46 NO 3 Xu et al. Effect of nano-Al 2 O 3 on erosion-corrosion behaviour of composite alloying layer Corrosion Engineering, Science and Technology 2011 VOL 46 NO 3 Xu et al. Effect of nano-Al 2 O 3 on erosion-corrosion behaviour of composite alloying layer Corrosion Engineering, Science and Technology 2011 VOL 46 NO 3

Investigation of corrosion resistance of electrodeposited Ni–W/SiC composite coatings

“…Electrodeposition of composite coatings, based on hard particles dispersed in a metallic matrix, is gaining much importance for potential engineering applications (in the chemical, mechanical and electronic industries). 8 The second phase can be hard oxide (Al 2 O 3 , ZrO 2 , TiO 2 and SiO 2 ), [9][10][11][12] carbides particles (SiC and B 4 C), 13,14 diamond, 15 solid lubricate (polytetrafluoroethylene, polychlorotrifluoroethylene and MoS 2 ) [16][17][18] and even liquid containing microcapsules. 19 Studies on Ni-W and Ni-W based coatings have become more frequent in recent years.…”